The US-built aircraft are among the 24 used supersonic fighters bought last year from Copenhagen for roughly $300 million, an exchange Milei's government described at the time as Argentina's most important military acquisition in 50 years.

"After a long wait, I finally have behind me the first six F-16 fighter jets," Milei said on the tarmac of a military base in Rio Cuarto, some 600 kilometers (373 miles) west of Buenos Aires.

"Thanks to this significant investment, we will considerably strengthen our air force."

Following a ceremony, Milei boarded one of the F-16 Fighting Falcons -- which had flown low over Argentina's capital before landing in Rio Cuarto -- and was seen smiling in the cockpit next to his sister Karina Milei, who serves as general secretary of the presidency, and Defense Minister Luis Petri.

"Hundreds of thousands of Argentines were able to look up and see their guardian angels in the sky for the first time," the president said.

When the sale was announced in April 2024, Argentina's defense ministry said the modernized Danish F-16s would form "the backbone of Argentina's air defense system."

They replace Argentina's French Mirage jets, the last of which were retired in 2017 after four decades of service.

The US administration of President Donald Trump, a Milei ally, approved the transfer of F-16s.

The US Embassy in Buenos Aires said in a statement Saturday that Argentina's jet acquisition marks "a major step in the country's efforts to modernize its air capabilities and deepen defense cooperation with the United States."

It said the delivery was the first of four batches, with six additional aircraft to be delivered to Argentina each December through 2028.